Liquid jetting device

ABSTRACT

The present invention is a liquid ejecting apparatus including: a carriage that reciprocates in a main scanning direction; a liquid ejecting head mounted on the carriage, having a plurality of head-liquid-supplying ports and a plurality of nozzles; and a sub-tank member mounted on the carriage, having a plurality of liquid-storing-room openings that are respectively communicated with the plurality of head-liquid-supplying ports of the liquid ejecting head. The sub-tank member is formed as a single integral member. Each of the plurality of liquid-storing-room openings is closed by an elastic partition having a predetermined area in order to form a liquid storing room. The plurality of liquid-storing-room openings are respectively communicated with a plurality of liquid-communication ways provided in the sub-tank member. The plurality of liquid-communication ways are respectively communicated with a plurality of sub-tank-liquid-supplying ports provided at an outside of the sub-tank member.

FIELD OF THE INVENTION

This invention relates to a liquid ejecting apparatus comprising acarriage on which a liquid ejecting head and a sub tank is mounted,wherein a liquid is supplied from a liquid supplying source arranged ona side of a main unit to a liquid storing room of the sub tank through aliquid supplying way, the liquid is stored in the liquid storing room,and the liquid stored in the liquid storing room is supplied to theliquid ejecting head.

BACKGROUND OF THE INVENTION

Various types of liquid ejecting apparatuses for ejecting liquid from anozzle are known. A typical one is an ink-jetting recording apparatus.

As shown in JP Laid-Open Publication No. 2001-232808 and JP Laid-OpenPublication No. 2002-211003, an ink-jetting printer that is a typicalexample of ink-jetting recording apparatus ejects an ink drop toward arecording medium such as a recording paper, in order to record an imageor characters.

For a printer coping with a large recording paper such as an “A0” sizeand/or for a printer coping with a large number of printing operationsfor a commercial use or the like, it is necessary to contain a largeamount of ink, because a consumption amount of ink is large. Inaddition, in a printer capable of printing with many color inks, it isnecessary to contain the respective color inks. Thus, an ink supplyingsource that can contain a large amount of ink, such as an ink tank or anink cartridge, is arranged at a main unit of the printer. The ink issupplied from the ink supplying source to a recording head through anink supplying tube.

In the above construction, in order to stabilize supply of the ink tothe recording head, the sub tank is mounted on a carriage.Conventionally, each sub tank is mounted for each kind of ink. The inksupplied from the ink supplying source through the ink supplying tube istemporarily stored in an ink storing room of the sub tank, and then issupplied to the recording head. Preferably, a part of the ink storingroom is formed by an elastic partition. In the case, the elasticpartition can absorb pressure fluctuation of the ink caused by a mainscanning operation of the carriage, so that the supply of the ink to therecording head is stabilized.

Herein, it is preferable that components of the ink-jetting recordingapparatus are made as small as possible in order to positively advanceconpactification of the apparatus and reduction of cost. If independentsub tanks are mounted on the carriage for the respective kinds of ink,the number of kinds of components and the number of the components arelarge depending on the number of the kinds of ink, which isdisadvantageous for the reduction of cost. In addition, the number ofassembling steps is also large. Furthermore, if each ink supplying tubeis connected to each sub tank, the total ink supplying tubes takes alarge space, and connecting operations thereof are much troublesome.

SUMMARY OF THE INVENTION

This invention is developed by focusing the aforementioned problems inorder to resolve them effectively. The object of this invention is toprovide a liquid ejecting apparatus wherein construction of a sub tankis much simplified and wherein absorbing function of pressurefluctuation in the sub tank is much improved.

This invention is a liquid ejecting apparatus comprising: a carriagethat reciprocates in a main scanning direction; a liquid ejecting headmounted on the carriage, having a plurality of head-liquid-supplyingports and a plurality of nozzles; and a sub-tank member mounted on thecarriage, having a plurality of liquid-storing-room openings that arerespectively communicated with the plurality of head-liquid-supplyingports of the liquid ejecting head; wherein the sub-tank member is formedas a single integral member; each of the plurality ofliquid-storing-room openings is closed by an elastic partition having apredetermined area in order to form a liquid storing room; the pluralityof liquid-storing-room openings are respectively communicated with aplurality of liquid-communication ways provided in the sub-tank member;and the plurality of liquid-communication ways are respectivelycommunicated with a plurality of sub-tank-liquid-supplying portsprovided at an outside of the sub-tank member.

According to the invention, since the plurality of liquid storing roomsare formed in the single sub tank member, it is not necessary to formthe plurality of liquid storing rooms as separate components, which iseffective in simplifying construction.

For example, the plurality of liquid-storing-room openings have bottoms.In the case, it is preferable that all the plurality ofliquid-storing-room openings are provided on one side of the sub-tankmember. In addition, it is preferable that opening surfaces of theplurality of liquid-storing-room openings are located in a common flatplane.

In such a case, all the plurality of liquid-storing-room openings may beclosed by a common elastic partition. In the case, arrangement of theelastic partition is completed by one step, so that simplification ofmanufacturing steps is promoted.

A part of each of the plurality of liquid-communication ways may beformed by a liquid-communication-way opening formed in the sub-tankmember and an elastic partition closing the liquid-communication-wayopening.

In the case, for example, the plurality of liquid-communication-wayopenings may be formed in parallel grooves. In the case, it is easy toform the plurality of liquid-communication-way openings.

In addition, it is preferable that all the plurality ofliquid-storing-room openings and all the plurality ofliquid-communication-way openings are closed by a common elasticpartition. In the case, forming of the plurality of liquid storing roomsand forming of the plurality of liquid communication ways are completedby one arranging step of the elastic partition, so that simplificationof manufacturing steps is promoted.

Alternatively, all the plurality of liquid-storing-room openings may beclosed by a common first elastic partition, and all the plurality ofliquid-communication-way openings may be closed by a common secondelastic partition.

The elastic partition may be adhesively jointed to the sub-tank memberin order to form the liquid storing rooms and the liquid communicationways.

In addition, it is preferable that the plurality ofsub-tank-liquid-supplying ports is gathered. In the case, a member suchas a liquid supplying tube forming the liquid supplying way is connectedto the sub-tank-liquid-supplying port gathered and arranged at oneposition, so that a space necessary for connecting them may be reducedas much as possible. Thus, the sub tank may be made much more compactcompared with prior art wherein a liquid supplying tube is connected toeach of the plurality of sub tanks that are arranged independently.

In addition, it is preferable that the elastic partition closing each ofthe plurality of liquid-storing-room openings is arranged in parallelwith the main scanning direction. In the case, when the sub-tank memberis moved forward and backward in the main scanning direction, aninertial force by an inertial mass of the liquid in the liquid storingroom doesn't act on the elastic partition directly. That is, the elasticpartition can maintain a function of absorbing pressure fluctuation ofthe liquid within a normal range by means of elastic characteristicsthereof. In particular, when the moving direction is turned over at anend portion of a main scanning range, the sub tank is deceleratedrapidly and the inertial force acts on it greatly. However, even in sucha situation the normal function of the elastic partition may bemaintained. In addition, it is also advantageous in improving durabilityof the elastic partition itself.

In addition, it is preferable that the elastic partition closing each ofthe plurality of liquid-storing-room openings is arranged substantiallyhorizontally. In the case, a depth of the liquid storing room in aperpendicular direction with respect to the elastic partition may bemade smaller, so that dimensions of the sub tank in the perpendiculardirection may be made as small as possible. Thus, an occupancy spacerequired near the carriage may be reduced.

Alternatively, the plurality of liquid-storing-room openings is throughopenings. In the case, elastic partitions are arranged at two positionsfor one liquid storing room. Thus, effective areas of the elasticpartitions may be made as large as possible, so that a volume of theliquid storing room may be made as small as possible. Thus, the sub tankmay be made compact, which is effective in reducing required space andcost.

In the case, it is preferable that opening surfaces on one side of theplurality of liquid-storing-room openings are located in a common firstflat plane, opening surfaces on the other side of the plurality ofliquid-storing-room openings are located in a common second flat plane,and the first flat plane and the second flat plane are parallel witheach other.

In such a case, opening surfaces on one side of the plurality ofliquid-storing-room openings may be closed by a common first elasticpartition, and opening surfaces on the other side of the plurality ofliquid-storing-room openings may be closed by a common second elasticpartition. In the case, arrangement of the elastic partitions iscompleted by one step for each side, so that simplification ofmanufacturing steps is promoted.

Alternatively, the invention is a liquid ejecting apparatus comprising:a carriage that reciprocates in a main scanning direction; a liquidejecting head mounted on the carriage, having a plurality ofhead-liquid-supplying ports and a plurality of nozzles; and a sub-tankmember mounted on the carriage, having a plurality ofliquid-storing-room openings that are respectively communicated with theplurality of head-liquid-supplying ports of the liquid ejecting head;wherein each of the plurality of liquid-storing-room openings is closedby an elastic partition having a predetermined area in order to form aliquid storing room; the plurality of liquid-storing-room openings arerespectively communicated with a plurality of liquid-communication waysprovided in the sub-tank member; the plurality of liquid-communicationways are respectively communicated with a plurality ofsub-tank-liquid-supplying ports provided at an outside of the sub-tankmember; and the plurality of sub-tank-liquid-supplying ports aregathered.

According to the invention, a member such as a liquid supplying tubeforming the liquid supplying way is connected to thesub-tank-liquid-supplying port gathered and arranged at one position, sothat a space necessary for connecting them may be reduced as much aspossible. Thus, the sub tank may be made much more compact compared withprior art wherein a liquid supplying tube is connected to each of theplurality of sub tanks that are arranged independently.

For example, the elastic partition is formed by a synthetic resin film.For example, the synthetic resin film is a polyphenylene-sulfide film ora polyimide film. These films have a sufficient chemical durabilityagainst the liquid and a compliance function suitable for the pressurefluctuation of the liquid.

In addition, at least one of the liquid storing rooms and the liquidcommunication ways may have a valve mechanism that is opened by anegative pressure caused by liquid reduction.

In addition, the invention is a sub-tank member comprising: a pluralityof liquid-storing-room openings that are respectively communicated witha plurality of head-liquid-supplying ports of a liquid ejecting head; aplurality of liquid-communication ways that are respectivelycommunicated with the plurality of liquid-storing-room openings; and aplurality of sub-tank-liquid-supplying ports that are respectivelycommunicated with the plurality of liquid-communication ways; whereineach of the plurality of liquid-storing-room openings is closed by anelastic partition having a predetermined area in order to form a liquidstoring room; the sub-tank member is mounted on a carriage thatreciprocates in a main scanning direction; and the sub-tank member isformed as a single integral member.

Alternatively, the invention is a sub-tank member comprising: aplurality of liquid-storing-room openings that are respectivelycommunicated with a plurality of head-liquid-supplying ports of a liquidejecting head; a plurality of liquid-communication ways that arerespectively communicated with the plurality of liquid-storing-roomopenings; and a plurality of sub-tank-liquid-supplying ports that arerespectively communicated with the plurality of liquid-communicationways; wherein each of the plurality of liquid-storing-room openings isclosed by an elastic partition having a predetermined area in order toform a liquid storing room; the sub-tank member is mounted on a carriagethat reciprocates in a main scanning direction; and the plurality ofsub-tank-liquid-supplying ports are gathered.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of an ink-jetting printer of a firstembodiment according to the invention;

FIG. 2(A) is a perspective view of the carriage and the sub tank;

FIG. 2(B) is a sectional view taken along a line B-B of FIG. 2(A);

FIG. 3(A) is a longitudinal sectional view of the carriage and the subtank;

FIG. 3(B) is a sectional view taken along a line B-B of FIG. 3(A);

FIG. 3(C) is a sectional view taken along a line C-C of FIG. 3(A);

FIG. 4 is a perspective view of a carriage and a sub tank in anink-jetting recording apparatus of a second embodiment according to theinvention;

FIG. 5(A) is a perspective view of a sub tank in an ink-jettingrecording apparatus of a third embodiment according to the invention;

FIG. 5(B) is a sectional view taken along a line B-B of FIG. 5(A);

FIG. 5(C) is a perspective view of the sub tank of FIG. 5(A) seen from abackside thereof;

FIG. 6(A) is a perspective view of a sub tank in an ink-jettingrecording apparatus of a fourth embodiment according to the invention;

FIG. 6(B) is a sectional view taken along a line B-B of FIG. 6(A);

FIG. 7 is a sectional view of a variant of the sub tank in theink-jetting recording apparatus of the fourth embodiment according tothe invention;

FIG. 8 is a perspective view of a sub tank in an ink-jetting recordingapparatus of a fifth embodiment according to the invention;

FIG. 9 is a perspective view of a sub tank in an ink-jetting recordingapparatus of a sixth embodiment according to the invention;

FIG. 10 is sectional views of an ink communication way and an inkstoring room wherein a self-sealing valve mechanism is provided, inwhich FIG. 10(A) is a sectional view showing a valve-closed state andFIG. 10(B) is a sectional view showing a valve-opened state;

FIG. 11 is a schematic view showing a supporting hole and cut-off holesformed in the partition of the sub tank;

FIG. 12 is an enlarged sectional view for explaining a state wherein amovable valve has been moved at maximum;

FIG. 13 is a sectional view of a sub tank wherein a variant of theself-sealing valve mechanism is provided;

FIG. 14 is a sectional view of a sub tank wherein another variant of theself-sealing valve mechanism is provided;

FIG. 15(A) is a sectional view of a sub tank wherein further anothervariant of the self-sealing valve mechanism is provided; and

FIG. 15(B) is a perspective view of the flat spring in FIG. 15(A).

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be described withreference to drawings.

FIG. 1 is a schematic plan view of an ink-jetting printer 1(hereinafter, referred to as printer 1) that is an ink-jetting recordingapparatus as a first embodiment according to the invention. FIG. 2(A) isa perspective view of a carriage 2 seen from an obliquely upsidethereof. FIG. 2(B) is a sectional view taken along a line B-B of FIG.2(A). FIG. 3(A) is a longitudinal sectional view of the carriage 2 and asub tank 3. FIG. 3(B) is a sectional view taken along a line B-B of FIG.3(A). FIG. 3(C) is a sectional view taken along a line C-C of FIG. 3(A).

As shown in FIG. 1, the printer 1 is mainly formed by the carriage 2 anda printer main body 5, the sub tank 3 and a recording head 4 beingmounted on the carriage 2. In the printer main body 5, provided are ahead scanning mechanism that causes the carriage 2 to reciprocate in amain scanning direction, a paper feeding mechanism that feeds arecording paper 6 in a paper-feeding direction, a recovering mechanismthat recovers a function of the recording head 4 that may bedeteriorated by increase in viscosity of ink, and ink tanks 20A, 20B,20C, 20D (a kind of ink supplying source) in which the ink to besupplied to the recording head 4 is stored.

As shown in FIG. 2(A), the carriage 2 has a mount base 10 formed in asubstantially rectangular plate. The sub tank 3 is provided on a side ofan upper surface of the mount base 10. The recording head 4 is providedon a side of a lower surface thereof. In more detail, a connecting frame11 for connecting the sub tank 3 onto an upper surface of the mount base10 is provided. Inside the connecting frame 11, ink supplying needles12A, 12B, 12C, 12D and needle filters 13 are arranged (see FIG. 3). Theink supplying needles 12A, 12B, 12C, 12D and the needle filters 13 areprovided correspondingly to a plurality of ink storing rooms 8A, 8B, 8C,8D formed in the sub tank 3. In addition, as shown in FIG. 3, therecording head 4 is directly jointed to the lower surface of the mountbase 10. Channel-forming parts 14 are formed at a lower portion of theconnecting frame 11. Ink introducing ways 15 are formed in thechannel-forming parts 14, and are communicated with ink introducing ways15′ provided in the mount base 10. Thus, ink introducing ways 15, 15′extend from the needle filters 13 to the recording head 4.

The head-scanning mechanism is formed by: a guide member 9 horizontallyextending in a housing, a pulse motor 16 arranged at a side portion ofthe housing, a driving pulley 17 connected to a rotational shaft of thepulse motor 16, a free pulley 18 mounted at the other side portion ofthe housing, a timing belt 19 connected to the carriage 2 and goingaround the driving pulley 17 and the free pulley 18, and a controllingpart (not shown) that controls rotation of the pulse motor 16. Thus, thecarriage 2 i.e. the recording head 4 can reciprocate in the mainscanning direction i.e. in a width direction of the recording paper 6,by driving the pulse motor 16.

In addition, in the present embodiment, four kinds of inks are used.Therefore, four ink storing rooms 8A, 8B, 8C, 8D are arranged alongsidein the main scanning direction in the sub tank 3. The number of the inkstoring rooms is not limited to four. If six color inks are used, sixink storing rooms may be arranged.

As shown in FIG. 1, the four ink tanks (or cartridges) 20A, 20B, 20C,20D for four color inks are arranged at a side end portion of theprinter main body 5. Ink supplying tubes 21A, 21B, 21C, 21D that extendfrom them are connected to a branch part of the sub tank 3 (describedbelow). The sub tank 3 may be continuously used as it is even when theink tanks are replaced.

The sub tank 3 is formed by a single sub-tank-forming member (sub-tankmember) 22 and an elastic sheet 31 described below. For example, thesub-tank-forming member 22 may be formed by an injection molding from asynthetic resin material such as polyethylene or polypropylene.

The sub-tank-forming member 22 has a plate-like shape with a largethickness as a whole. Four concave bottom-having ink-storing-roomopenings (opening holes) are formed in the sub-tank-forming member 22alongside in the main scanning direction. The ink-storing-room openingsare sealed by the elastic sheet 31 in order to form the ink storingrooms 8A, 8B, 8C, 8D. Opening surfaces of the four ink-storing-roomopenings of the sub-tank-forming member 22 are located in a common flatplace 23. In addition, in the sub-tank-forming member 22 of the presentembodiment, four communication-way openings are formed, which are openat the edge surface 23. The four communication-way openings are formedin parallel grooves. Each of the communication-way openings iscommunicated with each of the ink-storing-room openings.

A part of the sub-tank-forming member 22 forms the branch part 25, whichhas a substantially rectangular parallelepiped shape. A connection-jointforming surface 26 is formed in the branch part 25. Pipe-shapedconnection joints 27A, 27B, 27C, 27D are provided on theconnection-joint forming surface 26 to protrude therefrom. Ink supplyingtubes 21A, 21B, 21C, 21D are respectively connected to the pipe-shapedconnection joints 27A, 27B, 27C, 27D. In the present embodiment, thecommunication-way openings extend to the branch part 25, and the edgesurface 23 is different from the connection-joint forming surface 26.

The communication-way openings are sealed by the elastic sheet 31 so asto form communication ways 29A, 29B, 29C, 29D, which supply respectiveinks from the branch part 25 to the ink storing rooms 8A, 8B, 8C, 8D.The respective communication ways 29A, 29B, 29C, 29D are communicatedwith the respective connection joints 27A, 27B, 27C, 27D via insidecommunication ways 30A, 30B, 30C, 30D formed inside the branch part 25.

The elastic sheet 31 that is an elastic partition is adhesively jointedto the edge surface 23 by means of adhesive agent. Thus, the respectiveink storing rooms 8A, 8B, 8C, 8D have a function of absorbing pressurefluctuation. The elastic sheet 31 is formed by a synthetic resin filmsuch as a polyphenylene-sulfide film or a polyimide film.

In the present embodiment, the edge surface 23 is adjusted to besubstantially parallel with the main scanning direction of the carriage2. Thus, the elastic sheet 31 jointed to the edge surface 23 is alsosubstantially parallel with the main scanning direction of the carriage2.

As shown in FIGS. 2(A) and 3(A), on the side of the lower surface of thesub tank 3, cylindrical needle-connection parts 32A, 32B, 32C, 32Dcommunicated with the respective ink storing rooms 8A, 8B, 8C, 8D arearranged just under the respective ink storing rooms 8A, 8B, 8C, 8D.When the sub tank 3 is mounted on the carriage 2, respective inksupplying needles 12A, 12B, 12C, 12D of the connection frame 11relatively enter the insides of the respective needle-connection parts32A, 32B, 32C, 32D. Thus, the ink storing rooms 8A, 8B, 8C, 8D arecommunicated with the nozzles of the recording head 4 via the respectiveink supplying needles 12A, 12B, 12C, 12D, the ink introducing ways 15,15′, and the like. Herein, in FIG. 3, numeral signs 33A, 33B, 33C, 33Drepresent sealing members made of rubber.

As described above, the four needle-connection parts 32A, 32B, 32C, 32Dare engaged with the ink supplying needles 12A, 12B, 12C, 12D via thesealing members 33A, 33B, 33C, 33D at the same time. Thus, jointrigidity of the sub tank 3 and the carriage 2 is high, that is, the subtank 3 may be fixed stably.

As described above, the plurality of ink storing rooms 8A, 8B, 8C, 8D isformed by the single sub-tank forming member 22 and the elastic sheet31. This is advantageous in simplifying structure, compared with a priorart wherein the plurality of ink storing rooms 8A, 8B, 8C, 8D is formedas separate components. In addition, the communication ways 29A, 29B,29C, 29D, 30A, 30B, 30C, 30D are also formed in the single sub-tankforming member 22. This is suitable for smoothness of ink flows.

In addition, the plurality of ink-storing-room openings formed in thesingle sub-tank forming member 22 form the ink storing rooms 8A, 8B, 8C,8D together with the elastic sheet 31 jointed to the edge surface 23.Thus, the structure of the ink storing rooms 8A, 8B, 8C, 8D isremarkably simplified. In addition, the plurality of ink storing rooms8A, 8B, 8C, 8D can be formed by one jointing step of the one elasticsheet 31 to the edge surface 23. This can promote facilitation ofmanufacturing steps.

In addition, the communication-way openings are open at the single edgesurface 23. Thus, the communication-way openings may be formed easily.Then, the communication ways 29A, 29B, 29C, 29D may be easily formed ingrooves by the communication-way openings. In particular, since the edgesurface 23 is covered by the one elastic sheet 31, forming of thecommunication ways 29A, 29B, 29C, 29D and forming of the respective inkstoring rooms 8A, 8B, 8C, 8D may be completed at the same time, whichmay reduce the manufacturing steps. In particular, when the elasticsheet 31 consists of one film member, the jointing step of the elasticsheet 31 may be further simplified.

In addition, the branch part 25, which is a base point of the ink supplyto the respective ink storing rooms 8A, 8B, 8C, 8D, is formed by a partof the sub-tank forming member 22. Thus, distribution of the pluralityof kinds of inks into the respective ink storing rooms 8A, 8B, 8C, 8Dmay be achieved by the simplified structure. In addition, the branchpart 25 can be made compact and can protrude from a main part of the subtank 3. This is suitable to make the sub tank 3 compact.

In addition, the ink supplying tubes 21A, 21B, 21C, 21D are connected ina gathered manner to the connection joints 27A, 27B, 27C, 27D, which arearranged in a gathered manner at the connection-joint forming surface26. Thus, a space necessary for connecting the ink supplying tubes 21A,21B, 21C, 21D and the branch part 25 may be reduced as much as possible.That is, the sub tank 3 may be arranged more compactly compared with aprior art wherein each tube is connected to each of the plurality of subtanks that are arranged independently.

Since the communication-way openings extend to the branch part 25(except for the connection-joint forming surface 26), the communicationways 29A, 29B, 29C, 29D have a smooth flow-way structure from the branchpart 25 to the ink storing rooms 8A, 8B, 8C, 8D. In addition, thestructure of the communication ways 29A, 29B, 29C, 29D is simple.

In addition, mounting posture of the sub tank 3 is set in such a mannerthat the elastic sheet 31 is substantially parallel with the mainscanning direction. Thus, when the sub tank 3 is moved forward andbackward in the main scanning direction, an inertial force by aninertial mass of the ink in the ink storing rooms 8A, 8B, 8C, 8D doesn'tact on the elastic sheet 31 directly. That is, the elastic sheet 31 canmaintain a function of absorbing pressure fluctuation of the ink withina normal range by means of elastic characteristics thereof. Inparticular, when the moving direction is turned over at an end portionof a main scanning range, the sub tank 3 is decelerated rapidly and theabove inertial force acts on it greatly. However, even in such asituation, the normal function of the elastic sheet 31 may bemaintained. In addition, it is also advantageous in improving durabilityof the elastic sheet 31 itself.

Next, FIG. 4 is a perspective view of a carriage in an ink-jettingrecording apparatus of a second embodiment according to the invention.

In the second embodiment, mounting posture of the sub tank 3 is set insuch a manner that the edge surface 23 is substantially horizontal.Then, the cylindrical needle-connection parts, not shown, are arrangedon a side opposite to the elastic sheet 31. The other structures aresubstantially the same as the first embodiment. The same parts arerepresented by the same numeral signs, and explanation thereof isomitted.

When the above structure is adopted, a depth of the ink storing rooms8A, 8B, 8C, 8D in a perpendicular direction with respect to the elasticsheet 31 may be made smaller, so that dimensions of the sub tank 3 inthe perpendicular (vertical) direction may be made small. Thus, anoccupancy space required near the carriage 2 may be reduced.

Next, FIGS. 5(A) to 5(C) are views showing a sub tank in a thirdembodiment according to the invention.

In the present embodiment, the ink-storing-room openings are also openat a flat reverse edge surface 34, oppositely to the edge surface 23. Asecond elastic sheet 31′ is jointed to the reverse edge surface 34. Theother structures are substantially the same as the first embodiment. Thesame parts are represented by the same numeral signs, and explanationthereof is omitted.

In the above structure, the respective ink storing rooms 8A, 8B, 8C, 8Dcan have the elastic sheets 31, 31′ at the two surfaces. Thus, effectiveareas of the elastic sheets 31, 31′ may be made as large as possible, sothat a volume of each liquid storing room 8A, 8B, 8C, 8D may be made assmall as possible. Thus, the sub tank 3 may be made more compact, whichis effective in reducing required space and cost.

Next, FIGS. 6(A) and 6(B) are views showing a sub tank in a fourthembodiment according to the invention.

In the present embodiment, parallel groove-like communication-wayopenings are formed on an upper part 35 of the sub-tank forming member22, instead of the edge surface 23. As shown in FIG. 6(B), a thirdelastic sheet 31″ that is a sealing member is adhesively jointed to thegroove-like communication-way openings, so that communication ways 29A′,29B′, 29C′, 29D′ are formed. The other structures are substantially thesame as the first embodiment. The same parts are represented by the samenumeral signs, and explanation thereof is omitted.

In the above structure, it is unnecessary to provide thecommunication-way openings at the edge surface 23. Thus, the area of theedge surface 23 may be reduced. Thus, dimensions of the sub tank 3 inthe longitudinal direction and in the transversal direction and the likemay be shortened. Thus, the sub tank 3 may be made compact. Inparticular, if such dimension shortening is effectively used in a heightdirection of the apparatus main body, the height of the apparatus mainbody may be effectively shortened. Herein, it is preferable that thethird elastic sheet 31″ consists of the same material as the elasticsheet 31.

In addition, as shown in FIG. 7 corresponding to FIG. 6(B), thethickness of the upper part 35 may be used so that communication ways29A″, 29B″, 29C″, 29D″ having a circular section may be formed.

Next, FIG. 8 is a perspective view showing a sub tank in a fifthembodiment according to the invention.

In the present embodiment, the four ink storing rooms 8A, 8B, 8C, 8D arearranged in a matrix of 2×2. The other structures are substantially thesame as the first embodiment. The same parts are represented by the samenumeral signs, and explanation thereof is omitted.

When the above structure is adopted, both longitudinal and transversaldimensions of the sub tank 3 can be within a size range of the carriage2, so that the sub tank 3 and the carriage 2 can be united compactly.

In addition, the present invention has a feature that the singlesub-tank forming member 22 is used. However, besides that feature, thepresent invention has another feature that the ink supplying ports(connection joints) of the sub tank are gathered.

Regarding the latter feature, FIG. 9 is a perspective view showing acarriage in a sixth embodiment according to the invention.

In the present embodiment, the sub-tank forming member 22 is formed by aplurality of components. That is, each sub-tank forming member 22A, 22B,22C, 22D has an ink storing room 8A, 8B, 8C, 8D, and the sub-tankforming members 22A, 22B, 22C, 22D are united by an adhesive agent. Inaddition, a communication-way member 22E in which communication-wayopenings are formed is formed as a separate member, and a part of thecommunication-way member 22E forms the branch part 25. Thecommunication-way member 22E and the sub-tank forming members 22A, 22B,22C, 22D are united by an adhesive agent or the like.

According to the above structure as well, substantially the same effectas the first embodiment can be obtained. In addition, the ink storingrooms 8A, 8B, 8C, 8D can be freely combined, depending on the number ofkinds of necessary inks. Thus, design of the sub tank 3 may be easilychanged. In addition, the sub-tank forming members 22A, 22B, 22C, 22Dand the communication-way member 22E may be manufactured in advance, anda variously specified sub tank 3 may be provided correspondingly to arequest at each time. Thus, the number of kinds of molds may be reduced,so that cost reduction may be promoted.

Herein, it is of course that two ink storing rooms may be formed in onesub-tank forming member.

In the above respective embodiments, the elastic sheets 31, 31′, 31″ mayconsist of a synthetic resin film such as a polyphenylene-sulfide filmor a polyimide film. These films have a sufficient chemical durabilityagainst the ink and a compliance function suitable for the pressurefluctuation of the ink. A thickness of the elastic sheet is not morethan 10 μm, preferably not more than 5 μm, in order to suitably copewith the pressure fluctuation in the ink storing rooms 8A, 8B, 8C, 8D.

In addition, the elastic sheets 31, 31′, 31″ may consist of a syntheticresin film having a relatively small Young's modulus such as apolyethylene film. In the case, compared with the polyimide film or thelike, the same effect may be obtained even if the thickness is doubled.In addition, the polyethylene film may be thermally jointed to a subtank made of polyethylene, which may achieve simplification inmanufacture.

In addition, the elastic sheets 31, 31′, 31″ may consist of a rubbermember such as a butyl rubber, a silicon rubber, a fluorine rubber or anelastomer. A sufficient effect may be obtained by a thickness of about0.4 mm. Such a rubber member has higher elastic operatingcharacteristics as a pressure dumper than the sheet made of a syntheticresin film. That is, such a rubber member may achieve a superior dumpingfunction.

In addition, in the above respective embodiments, in a center of eachportion forming each ink storing room 8A, 8B, 8C, 8D of the elasticsheet 31, a pressure-receiving plate made of a hard material may beattached. The pressure-receiving plate has to be so light that itdoesn't cause the elastic sheet 31 to move and doesn't give any changeto the pressure in the ink storing room when the carriage 2 moves in aprinting operation or the like. For example, it is preferable that thepressure-receiving plate is made of a plastic material such aspolyethylene or polypropylene.

The pressure-receiving plate may be thermally attached (heat sealed) tothe elastic sheet 31 in advance. Alternatively, it may be attachedthereto by means of an adhesive agent or an adhesive double coated tapeor the like. When the ink storing room is a very shallow cylindricalspace as described below, it is preferable that the pressure-receivingplate has a circular shape and is arranged concentrically with the inkstoring room.

FIG. 10 is sectional views of an ink communication way and an inkstoring room wherein a self-sealing valve mechanism is provided. In thecase, as shown in FIG. 10, the ink communication way 129 has acylindrical space of a small volume. A spring-receiving plate 133 isfitted at a side surface of a sub-tank forming member 122. The inkcommunication way 129 is sealed by the spring-receiving plate 133 and anelastic sheet 131′. The elastic sheet 131′ is thermally jointed (heatsealed) to the sub-tank forming member 122.

In addition, the sub-tank forming member 122 has a partition 135dividing the ink communication way 129 and the ink storing room 108. Asupporting hole 136 is formed in the partition 135. The supporting hole136 slidably supports a movable valve 138 described below. The movablevalve 138 consists of a plate-like member 138 a, and a rod member 138 bintegrally formed at a central portion of the plate-like member 138 a.The rod member 138 b can slidably move through the supporting hole 136.

In addition, a sealing coil spring 139 is arranged between theplate-like member 138 a and the spring-receiving plate 133. Because ofan action of the sealing spring 139, the plate-like member 138 a isbiased to the partition 135 by a small pressing force. On the otherhand, a circular sealing member 141 made of rubber is attached to thepartition 135 so as to surround the supporting hole 136. Thus, theplate-like member 138 a of the movable valve 138 is adapted to come incontact with the sealing member 141 by means of the biasing force of thesealing spring 139. For example, the sealing member 141 is an O-ring orthe like.

As enlarged and shown in FIG. 11, the supporting hole 136 formed in thepartition 135 has intermittent cut-off holes 142 a. Thus, an inkcommunication way extending from the ink communication way 129 to theink storing room 108 is secured. Then, the sealing member 141 isprovided on the partition 135 so as to surround the outside of the fourcut-off holes 142 a, although not shown in FIG. 11.

On the other hand, the ink storing room 108 is formed by a cylindricalconcave portion (ink-storing-room opening) and the elastic sheet 131.The elastic sheet 131 is hermetically attached to the edge surface, inwhich the concave portion is formed, by mean of a heat sealing unit.Then, as described above, the circular pressure-receiving plate 123 isconcentrically attached at the outside of the elastic sheet 131.

In addition, in the ink storing room 108, a negative-pressure-holdingcoil spring 140 is arranged around the rod member 138 b of the movablevalve 138. One end of the negative-pressure-holding spring 140 is heldby a circular convex portion formed on the partition 135. The other endof the negative-pressure-holding spring 140 is fixed to the elasticsheet 131 to pull the same. Then, the negative-pressure-holding spring140 biases the elastic sheet 131 in an expansion direction of the volumeof the ink storing room 108, when the pressure-receiving plate 123 movesto compress the ink storing room 108.

In the embodiment shown in FIG. 10, a diameter of thenegative-pressure-holding coil spring 140 is substantially the same asthat of the sealing spring 139 and is relatively small. Preferably, thenegative-pressure-holding spring 140 is adapted to come in contact witha substantially central portion of the pressure-receiving plate 123 viathe elastic sheet 131.

On the other hand, an ink outlet port 145 is formed at an uppermost partof the ink storing room 108. Then, an ink outputting groove communicatedwith the ink outlet port 145 of the ink storing room 108 is formed in acircular arc shape along the concave portion forming the ink storingroom 108. Herein, the ink outlet port 145 of the ink storing room 108and the ink outputting groove communicated therewith are formed in thesub-tank forming member 122 and sealed by the elastic sheet 131.

Then, an ink communication way formed by the ink outputting groove iscommunicated with nozzles of the recording head 4 via an inside inkcommunication way of the sub-tank forming member 122. In the presentembodiment, the ink outlet port 145 of the ink storing room 108 isformed at the uppermost part in a gravity direction. Thus, the inkstoring room 108 can be filled with the ink without leaving air (airbubbles), for example when the ink is introduced into the recordingapparatus for the first time.

Herein, in a non-printing state, that is, in a state wherein the ink isnot consumed, a spring load W1 of the sealing spring 139 is applied tothe plate-like member 138 a, and a pressing force P1 of the ink suppliedto the ink communication way 129 is also applied to the plate-likemember 138 a. Thus, as shown in FIG. 10(A), the plate-like member 138 acomes in contact with the sealing member 141 to form a valve-closedstate (self-sealing state).

On the other hand, in a printing state, that is, in a state wherein theink is consumed, as the ink in the ink storing room 108 is reduced, theelastic sheet 131 moves toward the sub-tank forming member 122. At thattime, the pressure-receiving plate 123 attached to the elastic sheet 131moves in a contracting direction of the volume of the ink storing room108 so as to compress the negative-pressure-holding coil spring 140. Inaddition, a central portion of the pressure-receiving plate 123 comes incontact with an end of the rod member 138 b via the elastic sheet 131.

Herein, a spring load of the negative-pressure-holding spring 140 isrepresented by W2, a displacement-counterforce of the elastic sheet 131itself is represented by Wd, and a negative pressure in the ink storingroom 108 caused by consumption of the ink is represented by P2. At thattime, if P2>W1+P1+Wd+W2, the elastic sheet 131 pushes the rod member 138b, so that the contact between the plate-like member 138 a and thesealing member 141 is released and a valve-opened state is formed asshown in FIG. 10(B).

Thus, the ink in the ink communication way 129 is supplied into the inkstoring room 108 via the cut-off holes 142 a. When the ink is introducedinto the ink storing room 108, the negative pressure in the ink storingroom 108 disappears. Then, the movable valve 138 moves in such a mannerthat the valve-closed state shown in FIG. 10(A) is formed again and thatthe ink supply from the ink communication way 129 to the ink storingroom 108 is stopped.

Herein, FIG. 10(B) shows an extremely exaggerated state regarding anopening-closing operation of the movable valve 138. Actually, theelastic sheet 131 is substantially in contact with the end of the rodmember 138 b forming the movable valve 138 to keep the balanced state,so that the valve is opened only a little as the ink is consumed. Thatis, the ink is supplied into the ink storing room 108 little by little.

The pressure-receiving plate 123 can receive an effect of thedisplacement of the elastic sheet 131 by the whole area of thepressure-receiving plate 123. Thus, the effect of the displacement ofthe elastic sheet 131 may be surely transmitted to the movable valve138. Then, reliability of the opening-closing operation by the movablevalve 138 may be improved.

In addition, the negative-pressure-holding spring 140 comes in contactwith the elastic sheet 131 and urges the pressure-receiving plate 123 inthe expansion direction of the volume of the ink storing room 108. Thisprevents displacement of the pressure-receiving plate 123 when thecarriage reciprocates, so that malfunction in the opening-closingoperation by the movable valve 138 may be effectively reduced.

The negative-pressure-holding spring 140 also effectively inhibits aneffect of the elastic sheet 131 to bulge out at a lower portion of theink storing room 108 because of gravity to the ink. That is, thenegative-pressure-holding spring 140 has a function to always maintain alittle negative pressure in the ink storing room 108. Thus, thepressure-receiving plate 123 attached to the elastic sheet 131 is alwaysmaintained in a vertical posture, so that malfunction in theopening-closing operation by the movable valve 138 may be effectivelyreduced.

In addition, even when the ink is supplied into the ink storing room108, the negative-pressure-holding spring 140 expands and functions tomaintain the little negative pressure in the ink storing room 108. Thus,pressure fluctuation in the ink storing room 108 may be reduced. Then,normal ink-drop ejecting operations from the nozzles in the recordinghead 4 may be assured.

In addition, according to the present embodiment, the negative pressurein the ink storing room 108 is adapted to be assured by the sum of thespring load by the negative-pressure-holding spring 140 and the springload of the sealing spring 139; In other words, the spring load can bedivided into that of the negative-pressure-holding spring 140 and thatof the sealing spring 139. Then, the spring load of the sealing spring139 for bringing the movable valve 138 in contact with the sealingmember 141 in the valve-closed state can be selected smaller.

Thus, the contact pressure to the sealing member 141 by the elastomerresin or the like may be reduced, so that abnormal deformation of thesealing member 141 may be prevented. In addition, it can be preventedthat an excessive spring load is applied to the sealing member 141.Thus, a problem may be avoided that impurities such as fats and fattyoils contained in the elastomer resin forming the sealing member 141 areinterfused into the ink.

On the other hand, in the above embodiment, when the movable valve 138is moved maximally, it is preferable that a relationship of respectivedimensions is determined in such a manner that there is left a furthercompressible stroke of the negative-pressure-holding spring 140. FIG. 12is a view for explaining such a relationship of dimensions.

In FIG. 12, a compressed (cohesive, appressed) height of the sealingspring 139 under a state wherein the movable valve 138 has been movedmaximally is represented by L1, and a compressed height of thenegative-pressure-holding spring 140 under the state is represented byL2. That is, the relationship of dimensions is set in such a manner thatthe negative-pressure-holding spring 140 is not appressed even when thesealing spring 139 is compressed to a cohesive state. In other words, ifa spring member of the same standard (dimensions) is used for thesealing spring 139 and the negative-pressure-holding spring 140, arelationship of L1<L2 is set. In the embodiment shown in FIG. 12, theink flows into the ink storing room 108 through gaps of thenegative-pressure-holding spring 140. Thus, if thenegative-pressure-holding spring 140 is compressed cohesively(appressed), the ink flow way may be closed, that is, the ink supply maybe stopped. Thus, it is preferable to avoid the problem by setting theabove L1<L2 or the like.

In addition, as shown in FIG. 13, compared with the embodiment shown inFIG. 10, the diameter of the negative-pressure-holding coil spring 140may be enlarged. In the case, the negative-pressure-holding spring 140is adapted to come in contact with a peripheral part of thecircle-shaped pressure-receiving plate 123 via the elastic sheet 131.

According to the above construction, the pressure-receiving plate 123comes in contact with the negative-pressure-holding spring 140 in thevicinity of the periphery thereof. Thus, inhibited is the effect of theelastic sheet 131 to bulge out at a lower portion of the ink storingroom 108 because of gravity to the ink. Thus, the pressure-receivingplate 123 is always maintained in a vertical posture, so thatmalfunction in the opening-closing operation by the movable valve 138may be effectively reduced.

Alternatively, as shown in FIG. 14, as a negative-pressure-holdingspring, a plurality of coil springs 140 a, 140 b having small coildiameters may be used. According to this construction as well, inhibitedis the effect of the elastic sheet 131 to bulge out at a lower portionof the ink storing room 108 because of gravity to the ink. Thus, thepressure-receiving plate 123 is always maintained in a vertical posture,so that malfunction in the opening-closing operation by the movablevalve 138 may be effectively reduced.

In addition, in the embodiment shown in FIG. 14, the two coil springs140 a, 140 b are used, but more coil springs may be used. When n coilsprings are used, if a spring load of the negative-pressure-holdingspring is represented by W2 as described above, a spring load of eachcoil spring has to be set to W2/n.

In addition, as shown in FIG. 15, as the negative-pressure-holdingspring, a plate spring 140A may be adopted. As shown in FIG. 15(B), bothend portions of the plate spring 140A are bent in the same direction toform a pair of leg portions 140 d, 140 e. In a central portion thereof,a standing cut portion 140 f is formed in a reverse direction to thebent direction of the leg portions.

In the above plate spring 140A, as shown in FIG. 15(A), one leg portion140 d is fixed to the sub-tank forming member 122 in the ink storingroom 108. In addition, the rod member 138 b of the movable valve isinserted into an opening formed by forming the standing cut portion 140f, and a tip part of the standing cut portion 140 f is adapted to comein contact with a substantially central portion of thepressure-receiving plate 124 via the elastic sheet 131.

According to the above construction as well, against the displacement ofthe pressure-receiving plate 123, the plate spring 140A can urge theelastic sheet 131 in the expansion direction of the volume of the inkstoring room 108.

The above description is given for an ink-jetting recording apparatus.However, this invention is intended to apply to general liquid ejectingapparatuses widely. A liquid may be glue, nail polish, electricallyconductive liquid (liquid metal) for forming an electric circuit, or thelike. In addition, this invention can be also applied to an apparatusfor manufacturing color filters of a display member such as a liquidcrystal display, an apparatus for ejecting electrode material used informing an electrode of an organic EL display, an FED (face emissiondisplay) or the like, an apparatus for ejecting organic liquid used inmanufacturing biochips, or the like.

1. A liquid ejecting apparatus comprising a carriage that reciprocatesin a main scanning direction, a liquid ejecting head mounted on thecarriage, having a plurality of head-liquid-supplying ports and aplurality of nozzles, and a sub-tank member mounted on the carriage,having a plurality of liquid-storing-room openings that are respectivelycommunicated with the plurality of head-liquid-supplying ports of theliquid ejecting head, wherein the sub-tank member is formed as a singleintegral member, each of the plurality of liquid-storing-room openingsis closed by an elastic partition having a predetermined area in orderto form a liquid storing room, the plurality of liquid-storing-roomopenings are respectively communicated with a plurality ofliquid-communication ways provided in the sub-tank member, and theplurality of liquid-communication ways are respectively communicatedwith a plurality of sub-tank-liquid-supplying ports provided at anoutside of the sub-tank member.
 2. A liquid ejecting apparatus accordingto claim 1, wherein the plurality of liquid-storing-room openings havebottoms.
 3. A liquid ejecting apparatus according to claim 2, whereinall the plurality of liquid-storing-room openings are provided on oneside of the sub-tank member.
 4. A liquid ejecting apparatus according toclaim 3, wherein opening surfaces of the plurality ofliquid-storing-room openings are located in a common flat plane.
 5. Aliquid ejecting apparatus according to any of claims 2 to 4, wherein allthe plurality of liquid-storing-room openings are closed by a commonelastic partition.
 6. A liquid ejecting apparatus according to any ofclaims 1 to 5, wherein a part of each of the plurality ofliquid-communication ways is formed by a liquid-communication-wayopening formed in the sub-tank member and an elastic partition closingthe liquid-communication-way opening.
 7. A liquid ejecting apparatusaccording to claim 6, wherein the plurality of liquid-communication-wayopenings are formed in parallel grooves.
 8. A liquid ejecting apparatusaccording to claim 6 or 7, wherein all the plurality ofliquid-storing-room openings and all the plurality ofliquid-communication-way openings are closed by a common elasticpartition.
 9. A liquid ejecting apparatus according to claim 6 or 7,wherein all the plurality of liquid-storing-room openings are closed bya common first elastic partition, and all the plurality ofliquid-communication-way openings are closed by a common second elasticpartition.
 10. A liquid ejecting apparatus according to any of claims 1to 9, wherein the plurality of sub-tank-liquid-supplying ports aregathered.
 11. A liquid ejecting apparatus according to any of claims 1to 10, wherein the elastic partition closing each of the plurality ofliquid-storing-room openings is arranged in parallel with the mainscanning direction.
 12. A liquid ejecting apparatus according to any ofclaims 1 to 11, wherein the elastic partition closing each of theplurality of liquid-storing-room openings is arranged substantiallyhorizontally.
 13. A liquid ejecting apparatus according to claim 1,wherein the plurality of liquid-storing-room openings are throughopenings.
 14. A liquid ejecting apparatus according to claim 13, whereinopening surfaces on one side of the plurality of liquid-storing-roomopenings are located in a common first flat plane, opening surfaces onthe other side of the plurality of liquid-storing-room openings arelocated in a common second flat plane, and the first flat plane and thesecond flat plane are parallel with each other.
 15. A liquid ejectingapparatus according to claim 13 or 14, wherein opening surfaces on oneside of the plurality of liquid-storing-room openings are closed by acommon first elastic partition, and opening surfaces on the other sideof the plurality of liquid-storing-room openings are closed by a commonsecond elastic partition.
 16. A liquid ejecting apparatus comprising acarriage that reciprocates in a main scanning direction, a liquidejecting head mounted on the carriage, having a plurality ofhead-liquid-supplying ports and a plurality of nozzles, and a sub-tankmember mounted on the carriage, having a plurality ofliquid-storing-room openings that are respectively communicated with theplurality of head-liquid-supplying ports of the liquid ejecting head,wherein each of the plurality of liquid-storing-room openings is closedby an elastic partition having a predetermined area in order to form aliquid storing room, the plurality of liquid-storing-room openings arerespectively communicated with a plurality of liquid-communication waysprovided in the sub-tank member, the plurality of liquid-communicationways are respectively communicated with a plurality ofsub-tank-liquid-supplying ports provided at an outside of the sub-tankmember, and the plurality of sub-tank-liquid-supplying ports aregathered.
 17. A liquid ejecting apparatus according to any of claims 1to 16, wherein the elastic partition is formed by a synthetic resinfilm.
 18. A liquid ejecting apparatus according to claim 17, wherein thesynthetic resin film is a polyphenylene-sulfide film or a polyimidefilm.
 19. A liquid ejecting apparatus according to any of claims 1 to18, wherein at least one of the liquid storing rooms and the liquidcommunication ways has a valve mechanism that is opened by a negativepressure caused by liquid reduction.
 20. A sub-tank member comprising aplurality of liquid-storing-room openings that are respectivelycommunicated with a plurality of head-liquid-supplying ports of a liquidejecting head, a plurality of liquid-communication ways that arerespectively communicated with the plurality of liquid-storing-roomopenings, and a plurality of sub-tank-liquid-supplying ports that arerespectively communicated with the plurality of liquid-communicationways, wherein each of the plurality of liquid-storing-room openings isclosed by an elastic partition having a predetermined area in order toform a liquid storing room, the sub-tank member is mounted on a carriagethat reciprocates in a main scanning direction, and the sub-tank memberis formed as a single integral member.
 21. A sub-tank member comprisinga plurality of liquid-storing-room openings that are respectivelycommunicated with a plurality of head-liquid-supplying ports of a liquidejecting head, a plurality of liquid-communication ways that arerespectively communicated with the plurality of liquid-storing-roomopenings, and a plurality of sub-tank-liquid-supplying ports that arerespectively communicated with the plurality of liquid-communicationways, wherein each of the plurality of liquid-storing-room openings isclosed by an elastic partition having a predetermined area in order toform a liquid storing room, the sub-tank member is mounted on a carriagethat reciprocates in a main scanning direction, and the plurality ofsub-tank-liquid-supplying ports are gathered.